Structural behaviour of n-tetracosane and n-hexacosane mixtures

New insights on the crystalline forms in binary systems of n-alkanes: Characterization of the solid ordered phases in the phase diagram tricosane + pentacosane

“…Indeed, experimental results on this system and on other binary systems and, in particular, on C 26 1 C 28 (the subject of another paper) have enabled us to characterize for the first time the three intermediate forms and to propose, therefore, a new phase diagram for the binary system C 23 -C 25 . The scope of this work is even wider since these phases are also observed in other binary systems [31][32][33][34][35][36][37][38][39][40][41] of n-alkanes [with a chain-length difference ͑Dn͒ equal to 1 or 2]. In other words, this paper leads to a complete characterization of all solid ordered forms observed in all binary systems of n-alkanes (the components belonging to the range C 16 to C 28 ).…”

“…The study of binary phase diagrams (temperature versus composition) has revealed a complex structural behavior of the mixed samples [28][29][30][31][32][33][34][35][36][37][38][39][40][41] where other forms than those seen in the components are observed and which are stabilized by mixing. The earliest binary phase diagram showing multiple one-phase domains at low temperature (temperature domain where the ordered phases are observed) is that of Lüth et al 28 for the system C 20 -C 22 .…”

“…The earliest binary phase diagram showing multiple one-phase domains at low temperature (temperature domain where the ordered phases are observed) is that of Lüth et al 28 for the system C 20 -C 22 . A single crystal of the mixed sample C 20 (0.75)C 22 (0.25) was analyzed and a space group was proposed ͑B b2 1 31 working on 24 mixed samples of the above system and in particular, on the diffraction pattern of the mixed sample studied by Gerson and Nyburg,29 could not index all the diffraction lines on the basis of the B b2 1 m structure.…”

“…Polymorphism of n-alkanes (C n H 2n12 ; hereafter denoted by C n ) and determination of binary phase diagrams [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] in the alkane family have been reported on in recent years in numerous publications. The polymorphism of n-alkanes is rather well known where many solid-solid phase transitions have been observed as a function of temperature.…”

n-Alkane Binary Molecular Alloys

“…Mixing of n-alkanes generally has a dramatic influence on the polymorphic relationships, in particular, when even (n in Cn is even) alkanes are mixed with odd alkanes. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In previous papers we have reported on the phase behavior of a number of individual binary systems. [16][17][18][19][20] For these systems all mixed phases were characterized as to their crystallographic properties.…”